Problem: Express your answer as a mixed number simplified to lowest terms. $18\dfrac{2}{7}-6\dfrac{4}{5} = {?}$
Answer: Find a common denominator for the fractions: $= {18\dfrac{10}{35}}-{6\dfrac{28}{35}}$ Convert ${18\dfrac{10}{35}}$ to ${17 + \dfrac{35}{35} + \dfrac{10}{35}}$ So the problem becomes: ${17\dfrac{45}{35}}-{6\dfrac{28}{35}}$ Separate the whole numbers from the fractional parts: $= {17} + {\dfrac{45}{35}} - {6} - {\dfrac{28}{35}}$ Bring the whole numbers together and the fractions together: $= {17} - {6} + {\dfrac{45}{35}} - {\dfrac{28}{35}}$ Subtract the whole numbers: $=11 + {\dfrac{45}{35}} - {\dfrac{28}{35}}$ Subtract the fractions: $= 11+\dfrac{17}{35}$ Combine the whole and fractional parts into a mixed number: $= 11\dfrac{17}{35}$